question_answer 5)

Define the following terms (a) Aestivation (b) Placentation (c) Actinomorphic (d) Zygomorphic (e) Superior Ovary (f) Perigynous Flower (g) Epipetalous

Answer:

(a) Aestivation The mode of arrangement of sepals or petals in floral bud with respect to the other members of the same whorl is known as aestivation. The main types of aestivattons are twisted, valvate, imbricate, etc. (b) Placentation The arrangement of ovules within the ovary is known as placentation. The main types of placentations are marginal, parietal, basal, free central and axile. (c) Actinomorphic When a flower can be cut into two equal radial halves in any radial plane passing through the centre, it is said to be actinomorphic, e.g., mustard. (d) Zygomorphic When a flower cannot be cut into two equal radial halves in any radial plane passing through the centre, it is said to be zygomorphic, e.g., pea. (e) Superior ovary In hypogymous flower, the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flower is said to be superior, e.g., mustard. (f) Perigynous flower If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level. Then this is known as a perigynous flower, e.g., plum, etc. (g) Epipetalous flower A flower in which the stamens are attached to the petals as in brinjal.